CORTICAL ELECTROPHYSIOLOGY IN MIGRAINE AND POSSIBLE PATHOGENETIC IMPLICATIONS

According to recent evoked potential studies a fundamental, probably p rotective, feature of cortical information processing, i.e., response habituation during stimulus repetition, is abnormal in migraine betwee n attacks. The deficient habituation is found for different sensory mo dalities and experimental paradigms: pattern-reversal visual evoked po tentials (same stimulus at a constant intensity), cortical auditory ev oked potentials (same stimulus at increasing intensities), and auditor y event-related potential obtained in a passive ''oddball'' paradigm ( novel stimulus). The abnormal information processing is an interictal cortical dysfunction most likely due to inadequate control by the so-c alled ''state-setting, chemically-addressed pathways'' originating in the brain stem, in particular by the serotonergic pathway, leading to a low preactivation level of sensory cortices. We propose that it may play a pivotal role in migraine pathogenesis in conjunction with the r eported decrease of brain mitochondrial energy reserve, by favouring a rupture of metabolic homeostasis and biochemical shifts capable of ac tivating the trigeminovascular system and, thus, of producing a, migra ine attack. We postulate that both the deficient habituation in inform ation processing and the deranged oxygen metabolism may have behaviora l correlates. Which of these abnormalities are inherited, acquired or both remains to be determined. (C) 1998 Wiley-Liss, Inc.